Handle lock for a cutting instrument

ABSTRACT

A cutting instrument comprising two blades having a common pivot point. The blades have a cutting portion and an actuating portion on opposite sides of the pivot point. A handle is provided for each blade. Means are provided on the actuating portion of each blade to lock the blade into a recess in the handle. The locking means have barbs which coact with the handle to overcome the tendency of the force applied when using the instrument to separate the blade portion from the handle.

[ 51 Aug. 8, 1972 3/1943 Armstron [54] HANDLE LOCK FOR A CUTTING2,313,858 306/41 2,941,294 6/1960 Vosbikianetal..........279/l04INSTRUMENT [72] Inventor: Francis Duprey m valley PrimaryExaminer-Theron E. Condon Mass- Attorney--Norman S. Blodgett [73]Assignee: Parker Manufacturing Company,

ABSTRACT instrument comprising two blades having a Worcester, Mass.

t. The blades have a cutting porg portion on opposite sides of the t. Ahandle is provided for each blade.

provided on the actuating portion of each means have barbs which coactwith the of the force applied a. a d w P h m e h h b, t 6 .m m e a MS 6m dm U ml. .1 tn 3 e d e h mm .m b m i W3 e mn m m mm mm k mm .W m m mmlm n n dw o w m s me m t-me d cmnm me 0.1 .r a AcfiPMbThw MM M //w 1 www57W Amm O w 4 9 3 WW1 3M4 m 0 0 m3 7 3 9 .0 1 m 3 a u" 3 n" t l t m 5mm. 00 mu l dtm H M m P Smk .ll 1]] 2 1|. 2 8 2 2 555 tion from thehandle.

[56] References Cited UNITED STATES PATENTS 429,118 6/1890Durell.......................

1 Claim, 3 Drawing Figures FA TE NTED 8 I973 3,681. 845

FRANCIS S. DUPRE Y IN VENTOR.

This application relates to an improved means for locking the blade of acutting instrument to its corresponding handle. Handles have beenprovided on cutting instruments for ease of operation and because bymaking the handle of a material of less density than metal, the totalweight of the instrument is reduced. It

has been known to secure handles to the blades of cutting instruments byuse of a ferrule. The blades are fitted into a recess in the handle andthe metal ferrule is driven over the handle, compressing it into contactwith the blade. Because great force is repetitively applied in severingmaterial with the cutting instrument, there has been a tendency of theferrule to loosen and the handle to separate from the blade. Whenadhesives have been used .to secure the handle to the blade in SUMMARYOF THE INVENTION It is an object of the present invention to provide ashear device comprising a pair of metallic blades pivoted together at acommon point and actuated by a pair of handles. Each blade has anactuating portion. At the extremity of this actuating portion there islocated a positive block means which engages the corresponding handle tolock the two units together in such a manner that the repeated use andflexing resulting therefrom will not weaken the connection between theblade and the handle.

It is a further object of this invention to provide a simple lockingdevice to lock a blade tool to a handle in such a manner that assemblythereof may be readily accomplished.

These and other objects are accomplished by affixing at the end of theactuating portion of the blade means a barbed locking device. Thislocking device comprises a substantially U-shaped flat element having aplurality of barbs on each side thereof. These barbs are directedoutwardly and upwardly in such a manner as to lock into position theactuating portion of the blade means when inserted into a recess in thehandle. In the shape of the locking means they are resilient in natureand thereby can be readily compressed during insertion into the recessin the handle. After insertion the barbs, again due to their resilientnature, positively engage the wall surface of the recess in the handlethereby resisting outward movement thereof.

present i 2 BRIEF DESCRIPTION OF THE DRAWINGS Other objects and featuresof-the invention will become more apparent by reference to theaccompanying drawings, of which:-

FIG. 1 is a top view of the shear mechanism employing the locking deviceof the present invention,

FIG. 2 is a side view of the device of FIG. I, and

FIG. 3 is a detailed view of the locking device of the fiwI kHON OF THEPREFERRED EMBODIMENTS I Referring to the drawings, a shear mechanism isshown in which a pair of blades 1,2 connected at a central pivot point 3have actuating portions 4,5 which, in turn, are operated by. handles6,7, respectively. There is appended to the terminal portion of eachactuating portion of the blade means a locking device 8. This lockingdevice 8 is a substantially U-shaped flat metallic element having aplurality of barbs 9 on each side thereof. The locking device 8 isattached to the actuating portions 4,5 of the blade means by riveting,pinning or the like. The barbs 9 are directed outwardly and upwardly insuch a manner that during operation they lock the actuating portions 4,5of the blade means into position in the recesses 10,1 1 in the handle.

It will be obvious to those skilled in the art that changes andmodifications may be made without departing from this invention in itsbroadest aspects and, therefore, the aim of the appended claims is tocover all such changes and modifications as in the true spirit and scopeof this invention.

I claim:

1. In a cutting instrument,

a. first and second cutting blades having a cutting portion on opposedportions connected at a common pivot point, and each having an actuatingportion,

b. a handle for each blade having a concavity into which the actuatingportion of its blade can be inserted,

c. a protuberance extending from a surface of the actuating portion, ina direction perpendicular to a line between the pivot point and a pointon the actuating portion farthest from the pivot point, and

d. a locking means, consisting of a substantially U- shaped flat platehaving a plurality of barbs extending from the legs of the U-shapedplate in a direction outwardly and toward the open end of the U-shapedplate, the U-shaped plate overlying said surface and being fixed to theprotuberance at the elbow in the U-shaped plate.

1. In a cutting instrument, a. first and second cutting blades having acutting portion on opposed portions connected at a common pivot point,and each having an actuating portion, b. a handle for each blade havinga concavity into which the actuating portion of its blade can beinserted, c. a protuberance extending from a surface of the actuatingportion, in a direction perpendicular to a line between the pivot pointand a point on the actuating portion farthest from the pivot point, andd. a locking means, consisting of a substantially U-shaped flat platehaving a plurality of barbs extending from the legs of the U-shapedplate in a direction outwardly and toward the open end of the U-shapedplate, the U-shaped plate overlying said surface and being fixed to theprotuberance at the elbow in the U-shaped plate.